Return on Assets Ratio and Asset Turnover Ratio United Systems reported the following financial data (in millions) in its annual report: 2018 2019 Net income Net sales.. Total assets $21,500 49,540 68,734 $16,134 52,250 78,128 If the company's total assets are $65,676 in 2017, calculate the company's (a) return on assets and (b) asset turnover for 2018 and 2019